Color changing hand soap composition

ABSTRACT

A composition can indicate whether hands have been washed for an approximate predetermined period of time. The composition includes a pH indicator and a delivery system. The delivery system contains a pH-altering compound. The delivery system is added to the pH indicator approximately when hand washing begins. A method of washing hands is also presented. The pH indicator is applied to the hands. The delivery system is applied to the hands approximately when hand washing begins. The pH indicator and delivery system are mixed. A system for washing hands is also presented. The system includes a pH indicator, a delivery system, and a dispenser that releases the pH indicator and delivery system to hands. The hands are washed until the pH indicator changes color.

This application is a divisional (and claims the benefit of priorityunder 35 USC 120) of U.S. application Ser. No. 10/690,582, filed Oct.23, 2003, now abandoned. The disclosure of the prior application isconsidered part of (and is incorporated by reference in) the disclosureof this application.

TECHNICAL FIELD

This disclosure relates to the promotion of hygiene, and moreparticularly, to facilitating effective hand washing by indicating theduration of the hand-washing process.

BACKGROUND

Conventional soaps used for hand washing do not indicate whether thesoap has been used for an appropriate amount of time for the process tobe effective. As a result, hands are often washed for too short anamount of time for the process to be effective in cleansing hands.Properly washing your hands is one of the best ways to prevent infectionand the spread of diseases. Doctors, nurses and other people who work inmedical settings have to wash their hands frequently to avoid spreadinginfective agents between patients or to themselves. Those who preparefood must keep clean hands so they do not put germs into the food theyare making. Also, childcare workers must wash their hands often so theydo not make children sick. In addition to professionals whose hygiene isregulated, individuals should be conscious of the germs on their hands.Turning doorknobs, handling money and coughing may transfer bacteria andviruses to one's hands, which can then be spread to other people's handsor to your mouth and eyes and cause infection. Anyone who prepares foodfor others can infect others if his or her hands are not properlycleaned. Many of the diseases spread this way are more inconvenient thana simple cold. Some examples are the flu, hepatitis A and typhoid. SeeWisconsin Department of Health and Family Services, “Hand Washing,”available at <http://healthlink.mcw.edu/article/955074416.html>Aug. 29,2002.

Approaches ensuring effective hand cleansing include antibacterial handrubs. One drawback with such hand rubs is that such rubs may dry handsmore than washing with soap. Another approach known involves applying adye that glows under a black light to hands prior to washing hands,washing hands, then analyzing the effectiveness of the hand-washingprocess by examining the hands under a black light. In addition, somehospitals use electronic devices that alert an employee if theemployee's hands were not effectively washed. Such approaches may beexpensive and fail to achieve widespread use. The present disclosure mayhave one or more of the following advantages. The disclosure can be aneasy, convenient, and inexpensive approach to facilitate effective handwashing.

SUMMARY

Hand washing compositions, methods, and systems are provided that canencourage proper hand washing as a way to promote good hygiene. Inparticular, the compositions, methods, and systems signal when handshave been washed for the recommended minimum amount of time, therebycontributing to an effective hand-washing process. The presentdisclosure can be used in a number of settings including, but notlimited to, private homes, hospitals, childcare centers, nursing homes,schools, restaurants, airports, and food-preparation and food-processingestablishments.

In one aspect, a composition that changes color during use includes a pHindicator and a delivery system. The delivery system can be added to thepH indicator approximately when hand washing begins. The delivery systemcontains a pH-altering compound. Upon washing the hands for anapproximate predetermined period of time, the pH indicator changescolor.

In another aspect, a method of washing hands for an approximatepredetermined period of time includes the steps of applying a pHindicator to the hands and applying a delivery system to the hands. Thedelivery system contains a pH-altering compound and is added to the pHindicator approximately when hand washing begins. The pH indicator ismixed with the delivery system.

In one implementation, a flavin may be used as the pH indicator. Theflavin may be a red cabbage isolate. The delivery system may alsoinclude alginate beads in addition to the pH-altering compound. In oneexample, the pH-altering compound may be a bicarbonate, such as NaHCO₃.The pH indicator may be present in a soap, either in a solid soap,liquid soap, or detergent.

In another aspect, a system for washing hands for an approximatepredetermined amount of time includes a pH indicator, a delivery system,and a dispenser. The delivery system comprises a pH-altering compound.The dispenser releases the pH indicator and the delivery system to theuser for washing hands. The hands are washed at least until the pHindicator changes color.

The dispenser may include at least two compartments. The firstcompartment can contain the pH indicator and the second compartment cancontain the delivery system, which contains the pH-altering compound.The soap or detergent may be introduced separately or contained ineither of those two compartments.

These and other implementations may have one or more of the followingadvantages. The implementations allow a determination of whether handshave been washed for at least an approximate predetermined period oftime. The color change can signal that the appropriate period of timehas lapsed. The predetermined period of time can be varied depending onthe hand washing needs. The delivery system used can be altered toincrease or decrease the time of release of the pH-altering compound.Alternatively, the concentration or composition of the pH-alteringcompound can be varied to increase or decrease the time of release.

The pH indicator can be added to a soap or detergent prior to handwashing or it can be added at the time of hand washing. The pH indicatorutilized can be varied so that the color change occurs between differentcolors. Alternatively, the pH-altering compound can be varied, so that agiven pH indicator changes to a different color with a differentpH-altering compound.

The details of one or more implementations are set forth in thedescription below. Other features, objects, and advantages will beapparent from the description and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a front perspective view of a soap dispenser in accordancewith one implementation. The dotted line represents the division betweentwo compartments, one containing the pH indicator and the othercontaining the delivery system.

FIG. 2 is a view of a horizontal section of the dispenser illustratingthe internal construction of the two-compartment implementation shown inFIG. 1.

DETAILED DESCRIPTION

In general, a composition for indicating whether hands have been washedfor an approximate predetermined period of time includes a pH indicatorthat changes color as the pH of the environment surrounding theindicator changes. The pH indicator can be a naturally occurringsubstance. For example, the pH indicator can be an anthocyanin pigmentmolecule such as a flavin. Any pH indicator can be used, including, butnot limited to, flavins and other anthocyanins. The pH indicator may beadded to hands as hand washing begins or it may be present in a soap ora detergent.

In addition to the pH indicator, the composition also includes adelivery system that is added to the pH indicator approximately whenhand washing begins. The delivery system contains a pH-alteringcompound. The pH-altering compound can either be an acidic or basiccompound and can alter the pH of the environment surrounding the pHindicator, thereby causing the pH indicator to change color to reflectthe change in the pH of the surrounding environment. Examples ofpH-altering compounds include, but are not limited to, a bicarbonatesuch as sodium bicarbonate (NaHCO₃), washing soda (Na₂CO₃), citric acid(C₆H₈O₇), and acetic acid (CH₃COOH). Examples of pH-altering compoundssuch as citric acid can be found in lemon juice, while acetic acid canbe found in vinegar. The pH-altering compound within the delivery systemis released over time. Depending on the delivery system utilized, therelease time can vary. The release time can also be predetermined, basedon the delivery system used, the amount of the compound being released,and the concentration of the compound being released. The predeterminedperiod of time can be greater than ten seconds, for example, fifteenseconds to two minutes.

Another aspect of the present disclosure is a method of washing handsfor an approximate predetermined period of time, which is determinedbased on the time required to achieve effective hand washing and mayvary in different circumstances. The recommended time is approximatelytwenty seconds for purposes of achieving clean hands in ordinary hygienecircumstances. However, the present disclosure can be modified to causea more rapid or slower delivery of the pH-altering compound so that thecolor change occurs in a different amount of time to indicate a longeror shorter time period of hand washing. Medical professionals, forexample, may need to wash their hands for a longer period of time toachieve even cleaner hands.

Calcium alginate beads can be used as a delivery system that releasesits contents in the amount of time that is the minimum recommended timefor effective hand washing. For example, alginate beads can be used torelease sodium bicarbonate approximately twenty seconds after additionto the pH indicator. In a preferred implementation, the beads areapproximately 1 mm to 3 mm in size.

At least two factors are known to affect the rate of release ofsubstances from alginate beads. One factor is the size of the substancebeing released from the beads. Larger substances require more time to bereleased. A second factor is the concentration of the chemical in thesolution that was mixed with the alginate solution. The higher theconcentration, the more rapidly the substance is released. Mechanicalforces, such as mixing and lathering, may also affect the release time.The beads may be created and then immediately mixed with a pH-alteringcompound to form the delivery system component of the composition, orthey may alternatively be stored in a 150 mM NaCl, 1 mM CaCl₂bead-storing solution.

In a further implementation of the composition the pH indicator used isflavin. Flavins can be obtained as an isolate from a variety of sources,including, but not limited to, red cabbage, apple skin, plums, poppies,cornflowers, and grapes. In one example, the flavin is a red cabbageisolate.

In a further implementation of the composition the delivery systemcomprises alginate beads and a pH-altering compound. The pH-alteringcompound may be NaHCO₃. In a further implementation of the composition,the pH indicator is present in soap, either in a solid soap or in aliquid soap. In a further implementation of the composition, the pHindicator is present in a soap or detergent.

As can be seen, many variations of the method are possible. For example,a stronger base can be used. A stronger base turns the flavin to a greenor yellow color. Alternatively, an acidic pH-altering compound can beused. Such a pH-altering compound would cause the flavin to turn a deepred color.

Many systems may be used to practice the method with the claimedcomposition for color-changing soaps. As one example, a system maycomprise a pH indicator, a delivery system that contains a pH-alteringcompound, and a dispenser that releases the pH indicator and deliverysystem to a user for washing hands. The hands are washed until the pHindicator changes color, at which time the color change indicates thatthe hands have been washed for an approximate predetermined amount oftime.

The following is an example of an implementation of a system and is notintended to limit the system. The system comprises a dispenserpossessing at least two chambers and a pump dispenser. One chambercontains a solution of alginate beads that contain sodium bicarbonateand a pH-altering compound, such as the pH-altering composition ofExample 1. The other chamber contains a pH indicator such as the reddishflavin of Example 1. The pH indicator may be contained within a soapsolution. To wash hands, the user compresses the pump to dispenseappropriate amounts of the contents of the chambers onto the user'shands. The user then begins mixing the compositions by rubbing his orher hands together. After an approximate predetermined period of timelapses, the color of the pH indicator changes. For example, if flavinobtained from red cabbage is used, the pH indicator is initially red incolor then changes color to purple when the approximate predeterminedperiod of time has passed.

EXAMPLE 1

Color-Changing Composition

The following is an example of an implementation of the composition andis not intended to limit the composition. This example was directed toan approximate predetermined time of twenty seconds, which is theminimum recommended amount of time for effective hand washing.

a. pH-Indicator Composition

Flavin was isolated from red cabbage. Approximately two cups of boilingwater were poured over approximately four cups of loosely packed cabbageleaves. The mixture was incubated at room temperature for approximatelyten to fifteen minutes. The cabbage leaves were removed from themixture. The remaining liquid, containing flavin, was boiled until thevolume of the liquid was reduced to approximately one quarter of thestarting volume of water. This flavin-containing pH indicator, which maybe stored at approximately 4° C., was slightly acidic and had a reddishcolor. Next, a pH indicator-soap solution was made by adding 25% (byvolume) water, 25% of the pH indicator solution, and 50% liquid handsoap. The liquid hand soap was slightly acidic, having a pH ofapproximately 6. The pH indicator soap solution was reddish in color.

b. Delivery System Composition

The pH-altering compound used in this example was sodium bicarbonate.The delivery system used was calcium alginate beads. To prepare thesodium bicarbonate-containing alginate beads, a 1.8% alginate solutionwas first made in sterile water. The solution was thenfilter-sterilized. Next, a near-saturated solution of sodium bicarbonatewas prepared at approximately room temperature. The alginate and sodiumbicarbonate solutions were combined in a volume ratio of approximatelytwo parts alginate solution to approximately one part sodium bicarbonatesolution. The resulting solution was mixed by inversion and monitored toensure the absence of air bubbles. To create the sodiumbicarbonate-containing alginate beads, the solution was added drop-wiseby pipette into a 1.5% CaCl₂ solution. The resulting mixture was stirredwith an automatic stirrer for approximately 5 minutes. The mixture wasthen left to stand for approximately 10 minutes. The resulting beadswere rinsed three times in sterile water. The resulting beads wereapproximately 1 mm to approximately 3 mm in diameter.

c. Final Composition

The pH indicator composition was then mixed with the Delivery SystemComposition to create the color-changing hand soap composition.

EXAMPLE 2

Method of Washing Hands with Color Changing Soap

The following is an example of an implementation of the method and isnot intended to limit of the method. The delivery system composition andpH-indicator containing composition from Example 1 were combined on thehands for washing. Specifically, about 2.5 mL of the pH indicator soapsolution was applied to the hands. Approximately 1.25 mL of the sodiumbicarbonate-containing alginate beads was then applied to the hands andthe hands were washed by rubbing them together and mixing the twocompositions. The color of the pH indicator changed from its startingreddish color to a purple color approximately twenty seconds afteraddition of the sodium bicarbonate-containing alginate beads.

A number of implementations have been described. Nevertheless, it willbe understood that various modifications may be made without departingfrom the spirit and scope of the disclosure. Accordingly, otherimplementations are within the scope of the following claims.

1. A method of washing hands for an approximate minimum period of timepredetermined to provide effective cleansing, the method comprising: a.providing a dual chamber dispenser containing a cleansing systemcomprising a first element and a second element formulated, upon mixingfor the minimum period of time, to indicate passing of the minimumperiod of time by a change of color; b. applying to a user's hands froma first chamber of the dual chamber dispenser the first element of thecleansing system, the first element containing a pH indicator, where thepH indicator is red cabbage isolate; c. applying to the user's handsfrom a second chamber of the dual chamber dispenser the second elementof the cleansing system comprising a soap or detergent and alginatebeads containing a pH-altering compound; and d. performing hand washingmotion of the user's hands for at least the minimum period of time, thehand washing motion mixing the cleansing system of the first elementcontaining the pH indicator and the second element comprising soap ordetergent and alginate beads containing the pH-altering compound andcausing the cleansing system to change color, for indication of passingof the minimum period of time predetermined to provide effectivecleansing.
 2. The method of claim 1 wherein the pH-altering compound isa bicarbonate.